_That kicking up the Heel behind, and twisting round upon one Leg, is
fine Scating._
There are two Methods of Scating, one is made Use of for the Sake of
Expedition and Conveyance from Place to Place, and is practised by the
Boors or Peasants in Holland; the other is calculated entirely for
Amusement, and answers the End of _Shining_ upon the Ice, and therefore is
suited for Gentlemen near Towns upon Canals, and broad Pieces of Water. The
first of these Methods is performed by throwing the Body into such an erect
Posture inclining a little upon the Outside of the Scate, and drawing in
the Hip gradually, as will describe small Curve upon the Ice; this Practice
of Scating eases the Inside of the Thigh, and rests it in such a Manner as
to allow it Time to regain Strength for the next Stroke, and therefore is
very useful in long Journies; or else as to the Article of Swiftness, a
straight Line will carry a Person on faster than a Curve, because while he
is describing a Curve he has more Ground to run over.
The other Method of Scating, which is known in England by the Name of
Rolling, is done upon the same Principle as the former, only as you have no
Occasion for Expedition, you have an Opportunity of dweling longer upon
your Strokes, and your Time; by which Means, instead of describing a small
Curve, you describe a large one.
It will be necessary to explain the Cause of this Motion, before we can
make the Reader sensible of what we intend to say.
All Bodies that are put into Motion upon the Surface of the Earth, are
acted upon by two Forces; namely, a Projectile Force and a Centripetal
Force. The Projectile Force is that which is given it by the Hand or
Strength of any Person, and the Centripetal Force is that which causes all
Bodies to seek the Center of the Earth. For Instance, when a Stone is cast
into the Air to any Distance, the Reason why it does not move on to
Eternity without stopping (as it ought to do by the Principles of
Mechanics) is, because the Centripetal Force keeps continually acting upon
it, till it has pulled it down to the Ground again: This serves to explain
what is meant by a Centripetal Force.
Now, when a Person scates, he is acted upon by these two Forces, as other
Bodies in Motion are. It is the Projectile Force which throws him upon the
Outside of the Scate, till he has got quite out of the Center of Gravity,
by which Means he would be pulled to the Ground by the Centripetal Force,
if he was not supported by the Projectile Force, which is strong enough to
make Head against the Centripetal for a little while (in the same Manner as
it is able to keep a Stone in the Air till it is spent) and by that Time
the Person scating has recovered himself into an erect Posture. This
Projectile Force is given by a Stroke of the Foot, inclined to the Plain of
the Ice; by which Means, the _whole_ Edge of the Scate takes hold, and is
your moving Force; and the more of the Edge of the Scate a Person uses in
his Stroke, the easier he will go to himself, and the greater Velocity he
will move with: For if he dwells more upon the Heel of the Scate than the
Toe, or vice versâ, he not only loses Part of his moving Force, by losing
Part of the Edge of his Scate, which is absolutely the moving Force, but he
likewise encreases his Friction, which ought to be destroyed as much as
possible; and at the same Time loses that Symmetry of Gesture, upon which
the Gracefulness of his Attitude depends.
When a Person scates properly, he keeps the Foot that he strikes with in
such a Posture upon the Ice, as to make the whole Scate take hold of it
sideways, without destroying his progressive Motion; and instead of kicking
up his Heel behind, just when he takes Leave of the Ice, with the Foot
which has been striking, he gives his Toe a Turn outwards, which not only
gives him a genteel Air, being according to the Rules of Dancing, but
likewise sends him with twice the Force upon the Outside, as it adds to
that Projectile Force which is to make Head against the Centripetal, and to
keep him upon his Legs after he has got out of the Center of Gravity; and
which uncommon Phoenomenon gives that Surprize and Pleasure to a Beholder,
which he perceives at the Sight of a fine Scater.
I mention this, because I have met with those who have obstinately
persisted in it, that some Persons who kick up their Heels behind, and
strike only with the Toe of their Scate, because they can go a Snail's
Gallop upon the Outside, are fine Scaters; when they are making Use of a
Method which is repugnant to the very Principles of Mechanics.
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